There is an astonishing degree of similarity between Advaita Vedanta and Valentinian Monism. Most people don't know that there are 33 Aeons(Gnosticism) in Christianity as well as in Hinduism.
"It is worth noting that Valentinianism shows an astonishing degree of similarity to another monistic system, the Advaita Vedanta school of Indian philosophy. In Advaita, the material world is an illusion (maya) attributed to ignorance (avidya) of the true reality. Through knowledge (jnana) of the ultimate reality (brahman), the world of multiplicity vanishes. True redemption (moksha) is the knowledge of one's true nature.
This raises the intriguing possibility of some kind of connection between the two. There was some awareness of Indian thought in the ancient Roman world. However, at the time of Valentinus, there was no systematic statement of Advaita thought. It is possible that Valentinus came into contact with some form of early Advaita Vedanta teaching. Advaita philosophy as it now stands was given its definitive form by Shankara in the 6th or 7th century AD. There also exists the possibility that he was influenced by Valentinian thought. Valentinians are known to have been active in the Middle East as late as the seventh century. It is possible that Valentinian missionaries or refugees may have made their way to India and come into contact with Shankara or his immediate predecessors. However, any connection between the two remains purely hypothetical."- Valentinian Monism